The ISIS conundrum

The U.S. should avoid doing anything that makes the situation in Syria and Iraq worse than it already is

America's coalition partners in Iraq and Syria are pressing the Obama administration to expand military action against the Islamic State militants who control large swaths of territory in both countries. Recently ISIS has captured more ground in eastern Syria, causing tens of thousands of refugees to flee and seek asylum in Europe. Meanwhile, congressional Republicans have joined the chorus of criticism aimed at what they see as the administration's failure to move more aggressively against ISIS, and they are demanding a change in U.S. strategy. That may be easier said than done, however: The truth is that whatever the U.S. ends up doing in Syria could just make matters worse.

For that reason President Barack Obama has been reluctant to ramp up the U.S. military role in Syria beyond airstrikes and a training mission for the moderate Syrian opposition. And he has flatly ruled out sending U.S. ground forces into the fray. Putting American boots on the ground could entangle us in an intractable conflict that would make the quagmire of Vietnam seem like a lark by comparison.

Start with the fact that the various factions fighting in Syria all have radically different agendas, most of which don't coincide with our own. The opposition to Syrian President Bashar Assad's brutal regime is a hodgepodge of radical Islamist groups, al-Qaida, the Islamic State, Sunni militias such as the Nussra Front and Kurdish fighters bent on carving out an independent Kurdistan along Turkey's border as well as the tiny contingent of so-called "moderate" Syrian rebels the U.S. is trying to train and equip. Mostly they all hate each other, and any effort to help one of them instantly makes enemies of all the rest.

The U.S. strategy so far has been to strike ISIS from the air in order to allow the Kurds and moderate Syrian opposition fighters to seize positions on the ground. But even the administration admits that plan isn't working as advertised. Part of the problem is that while the Kurds have proven the most effective fighters against ISIS' militants, they've also alienated the Sunni Arab civilians in the territories they control. The Arabs view the Kurds not as liberators but as an occupying force come to steal their lands. No wonder many of them have pledged their allegiance to ISIS.

Another problem involves the "moderate" Syrian opposition, which is small and pathetically weak as a military force. The U.S. wants these fighters to go after the Islamic State, which it considers the most dangerous actor in the conflict, but they want to focus on toppling Mr. Assad. Since ISIS shares the same goal, there's no assurance that after receiving American training and equipment the moderates won't bolt the U.S.-led coalition and throw in their lot with the extremists.

But the biggest challenge the U.S. faces in Syria is how to end the conflict there in a way that forces Mr. Assad to step down without creating a power vacuum that ISIS and its Islamist allies would rush to fill. The 2003 American invasion of Iraq quickly deposed President Saddam Hussein from power, but it also destroyed the Iraqi state institutions responsible for governing the country. That turned out to be a costly mistake that led to years of sectarian bloodletting and ethnic cleansing and reduced Iraq to chaos even as a huge U.S. occupation force struggled to restore order.

No doubt Mr. Obama had the example of Iraq in mind when he chose his strategy in Syria. There may be no good military option that will achieve the U.S. goal of pushing Mr. Assad out while simultaneously rolling back ISIS' hold on the region, no matter how many airstrikes or local forces on the ground the coalition musters. And given Russia's and Iran's continued support for the Assad regime, the chances for a negotiated settlement of the conflict appear bleak.

Despite the brutality of the war, Syria presents the U.S. with a delicate situation in which it must tread cautiously. It's easy for the president's critics to jump up and down shouting for more troops. But that's not a strategy if sending in the Marines only entangles us more deeply in a conflict that we probably can't win at any reasonable cost.